Receiver hardware reduction for spatially independent signals and associated methods

Abstract

A communications device includes an antenna array comprising antenna elements for receiving at least N spatially independent signals, and a receiver coupled to the antenna array. The receiver includes an analog receiver circuit for receiving the N spatially independent signals, and has a bandwidth of at least N times an information bandwidth of the spatially independent signals. The receiver further includes a digital receiver circuit coupled to the analog receiver circuit, and samples the N spatially independent signals at a rate of at least N times a Nyquist rate which would have been required if a single antenna element had been used to receive the signals. A processor is coupled to the digital receiver circuit for demultiplexing the sampled N spatially independent signals.

1. A communications device comprising:
 an antenna array comprising a plurality of antenna elements for receiving at least N spatially independent signals; 
 a receiver coupled to said antenna array and comprising
 an analog receiver circuit for receiving the N spatially independent signals, and having a bandwidth of at least N times an information bandwidth of the spatially independent signals, and 
 a digital receiver circuit coupled to said analog receiver circuit, and sampling the N spatially independent signals at a rate of at least N times a Nyquist rate which would have been required if a single antenna element had been used to receive the signals, and comprising an analog-to-digital converter for converting the N spatially independent signals to N spatially independent digital signals; 
 
 a controller coupled to said antenna array and comprising
 a switching circuit coupled to said antenna array for switching between said plurality of antenna elements for sampling the N spatially independent signals by said antenna array, and 
 a timing circuit coupled to said switching circuit for coordinating sampling of the N spatially independent signals by said antenna array based on sample timing of the N spatially independent digital signals by said analog-to-digital converter; and 
 
 a processor coupled to said digital receiver circuit for demultiplexing the sampled N spatially independent digital signals, and coupled to said timing circuit for providing the sample timing of the N spatially independent digital signals by said analog-to-digital converter. 
 
     
     
       2. A communications device according to  claim 1  wherein said digital receiver circuit comprises a single analog-to-digital converter. 
     
     
       3. A communications device according to  claim 1  wherein said processor demodulates in parallel the N spatially independent signals after having been demultiplexed, with the N demodulated signals then being combined for signal processing. 
     
     
       4. A communications device according to  claim 1  wherein said processor reconstructs the N independently transmitted signals. 
     
     
       5. A communications device according to  claim 1  wherein said plurality of antenna elements comprise N uncorrelated antenna elements. 
     
     
       6. A communications device according to  claim 1  wherein said plurality of antenna elements comprise N correlated antenna elements. 
     
     
       7. A communications device according to  claim 6  wherein said N correlated antenna elements comprise N active antenna elements so that said antenna array forms a phased array. 
     
     
       8. A communications device according to  claim 6  wherein said N correlated antenna elements comprise at least one active antenna element, and up to N−1 passive antenna elements so that said antenna array forms a switched beam antenna. 
     
     
       9. A communications device according to  claim 3  wherein the signal processing is based upon at least one of a knowledge based signal extraction process and a blind signal separation process. 
     
     
       10. A communications device according to  claim 9  wherein the blind signal separation process is based on at least one of principal component analysis (PCA), independent component analysis (ICA) and single value decomposition (SVD). 
     
     
       11. A communications device according to  claim 9  wherein the knowledge based signal separation process is based on at least one of a zero forcing (2F) process and a minimum mean squared estimation (MMSE) process. 
     
     
       12. A communications device according to  claim 1  wherein the N spatially independent signals correspond to a single transmitted signal. 
     
     
       13. A communications device according to  claim 1  wherein the N spatially independent signals correspond to N independently transmitted signals from a MIMO transmitter; and wherein said processor reconstructs the N independently transmitted signals. 
     
     
       14. A communications device according to  claim 1  further comprising:
 a transmitter; and 
 a switch coupled between said antenna array, said transmitter and said receiver so that the communications device operates in a half-duplex mode. 
 
     
     
       15. A communications device according to  claim 1  further comprising:
 a transmitter; and 
 at least one additional antenna element dedicated to said transmitter so that the communications device operates in a full-duplex mode. 
 
     
     
       16. A method for operating a communications device comprising an antenna array comprising a plurality of antenna elements, an analog receiver circuit coupled to the antenna array, a digital receiver circuit coupled to the analog receiver circuit comprising an analog-to-digital converter, a processor coupled to the digital receiver circuit, and a controller coupled to the antenna array and comprising a switching circuit coupled to the antenna array and a timing circuit coupled to the processor, the method comprising:
 receiving at least N spatially independent signals by the antenna array; 
 providing the N spatially independent signals to analog receiver circuit, the analog receiver circuit having a bandwidth of at least N times an information bandwidth of the spatially independent signals; 
 sampling in the digital receiver circuit the N spatially independent signals at a rate of at least N times a Nyquist rate which would have been required if a single antenna element had been used to receive the signals; 
 converting in the analog-to-digital converter the sampled N spatially independent signals to N spatially independent digital signals; 
 operating the switch controller for
 causing the switching circuit coupled to the antenna array to switch the plurality of antenna elements for sampling the N spatially independent signals by the antenna array based on operation of the switching circuit, and 
 causing the timing circuit coupled to the switching circuit to sample the N spatially independent signals by the antenna array based on a sample timing of the N spatially independent digital signals by the analog-to-digital converter; and 
 
 demultiplexing the sampled N spatially independent digital signals in the processor, and providing from the processor to the timing circuit the sample timing of the N spatially independent digital signals by the analog-to-digital converter. 
 
     
     
       17. A method according to  claim 16  wherein the digital receiver circuit comprises a single analog-to-digital converter. 
     
     
       18. A method according to  claim 16  wherein the processor demodulates in parallel the N spatially independent signals after having been demultiplexed, with the N demodulated signals then being combined for signal processing. 
     
     
       19. A method according to  claim 16  wherein the processor reconstructs the N independently transmitted signals. 
     
     
       20. A method according to  claim 16  wherein the plurality of antenna elements comprise N uncorrelated antenna elements. 
     
     
       21. A method according to  claim 16  wherein the plurality of antenna elements comprise N correlated antenna elements. 
     
     
       22. A method according to  claim 21  wherein the N correlated antenna elements comprise N active antenna elements so that the antenna array forms a phased array. 
     
     
       23. A method according to  claim 21  wherein the N correlated antenna elements comprise at least one active antenna element, and up to N−1 passive antenna elements so that the antenna array forms a switched beam antenna. 
     
     
       24. A method according to  claim 18  wherein the signal processing is based upon at least one of a knowledge based signal extraction process and a blind signal separation process. 
     
     
       25. A method according to  claim 16  wherein the N spatially independent signals correspond to a single transmitted signal. 
     
     
       26. A method according to  claim 16  wherein the N spatially independent signals correspond to N independently transmitted signals from a MIMO transmitter; and wherein the processor reconstructs the N independently transmitted signals. 
     
     
       27. A method according to  claim 16  wherein the communications device further comprises a transmitter, and a switch coupled between the antenna array, the transmitter and the receiver so that the communications device operates in a half-duplex mode. 
     
     
       28. A method according to  claim 16  wherein the communications device further comprises a transmitter, and at least one additional antenna element dedicated to the transmitter so that the communications device operates in a full-duplex mode.